User equipment and wireless communication method

ABSTRACT

Provided are a user equipment and a wireless communication method for LAA. The user equipment comprises: a receiver operative to receive a UL grant which schedules a subframe for UL transmission; a first circuit operative to perform LBT; a transmitter operative to transmit a PUSCH in the scheduled subframe starting from one available starting position of multiple candidate starting positions in the scheduled subframe if the LBT is successful. According to present disclosure, it is possible to increase the possibility that PUSCH could be sent in the scheduled subframe after LBT.

BACKGROUND 1. Technical Field

The present disclosure relates to the field of wireless communication,and in particular, to a user equipment (UE) and a wireless communicationmethod for Licensed-Assisted Access (LAA).

2. Description of the Related Art

Rapid growth of mobile data forces operators to utilize the finitefrequency spectrum with higher and higher efficiency, while plenty ofunlicensed frequency spectra are utilized less efficiently only byWi-Fi, Bluetooth, etc. LTE-U (LTE-unlicensed) and LAA (Licensed-AssistedAccess) could extend the LTE spectrum to unlicensed band that wouldaugment the LTE network capacity directly and dramatically.

SUMMARY

One non-limiting and exemplary embodiment provides an approach toincrease the possibility that PUSCH could be sent in the scheduledsubframe after LBT (Listen Before Talk).

In a first general aspect of the present disclosure, there is provided auser equipment for licensed-assisted access (LAA) comprising: a receiveroperative to receive an uplink (UL) grant which schedules a subframe forUL transmission; a first circuit operative to perform listen-before-talk(LBT); a transmitter operative to transmit a first physical uplinkshared channel (PUSCH) in the scheduled subframe starting from oneavailable starting position of multiple candidate starting positions inthe scheduled subframe if the LBT is successful.

In a second general aspect of the present disclosure, there is provideda wireless communication method for licensed-assisted access (LAA)performed by a user equipment, comprising: receiving an uplink (UL)grant which schedules a subframe for UL transmission; performinglisten-before-talk (LBT); transmitting a physical uplink shared channel(PUSCH) in the scheduled subframe starting from one available startingposition of multiple candidate starting positions in the scheduledsubframe if the LBT is successful.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several embodiments in accordance with thedisclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings, in which:

FIG. 1 schematically illustrates a situation where a partial subframe isadopted;

FIG. 2 illustrates a flowchart of a wireless communication methodaccording to an embodiment of the present disclosure;

FIG. 3 schematically illustrates a block diagram of a UE according to anembodiment of the present disclosure;

FIG. 4 schematically illustrates an embodiment of the present disclosurein which there are two candidate starting positions for PUSCH in asubframe;

FIG. 5 schematically illustrates RE mapping according to an embodimentof the present disclosure;

FIG. 6 schematically illustrates formation of one slot length PUSCH byusing the intra-subframe frequency hopping according to an embodiment ofthe present disclosure;

FIG. 7 schematically illustrates formation of one slot length PUSCH byusing mapping for a two-slot PUSCH according to an embodiment of thepresent disclosure;

FIG. 8 schematically illustrates an exemplary UL subframe structureaccording to an embodiment of the present disclosure; and

FIG. 9 schematically shows a burst with a partial subframe at the end ofthe burst to occupy the whole burst.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part thereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. It will be readily understood that the aspects ofthe present disclosure can be arranged, substituted, combined, anddesigned in a wide variety of different configurations, all of which areexplicitly contemplated and make part of this disclosure.

Different from distributed coordination systems such as Wi-Fi, LTE is aneNB-centric system in which both downlink and uplink data transmissionsare scheduled by an eNB. A UL grant for PUSCH (Physical Uplink SharedChannel) should be sent before the granted subframe (for example 4 msbefore the granted subframe). On the other hand, according to someregional requirements such as Europe, LBT (Listen Before Talk) isrequired for a transmitter, which could be either an eNB or a UE. Sincethe LBT result at the granted subframe is not known during the timesending the UL grant, when the UL grant has been sent but the UE cannotobtain the channel due to LBT failure, scheduling overhead as well asdelay would increase.

In order to increase the possibility that PUSCH could be sent at thescheduled subframe after LBT, a PUSCH which can start flexibly at aposition within a scheduled subframe subjected to LBT is introduced. Asubframe shorter than a normal subframe is referred to as a partialsubframe, and a PUSCH carried in a partial subframe is referred to as apartial PUSCH hereinafter. FIG. 1 schematically illustrates a situationwhere a partial subframe is adopted. As shown in FIG. 1, a UL grant issent from an eNB to a UE before the scheduled subframe. The UE performsLBT right before the scheduled subframe, but the LBT failed, that is,the channel is busy. In this case, the UE cannot send PUSCH startingfrom the subframe starting boundary of the scheduled subframe. Then, theUE may perform LBT again within the scheduled subframe. For example, asshown in FIG. 1, if the LBT within the scheduled subframe is successful,according to the present disclosure, a PUSCH can be sent starting from aposition within the scheduled subframe, for example, starting from thebeginning of the second slot of the scheduled subframe. The PUSCH canend at the subframe ending boundary of the scheduled subframe. The PUSCHstarting from a position within the scheduled subframe and ending at thesubframe ending boundary of the scheduled subframe is shorter than onesubframe and can be referred to as a partial PUSCH.

According to an embodiment of the present disclosure, there is provideda wireless communication method for LAA. FIG. 2 illustrates a flowchartof the wireless communication method 200. The wireless communicationmethod 200 can be performed by a UE and comprise steps 201-203. At step201, the UE receives a UL grant which schedules a subframe for ULtransmission. The UL grant can be sent by an eNB. At step 202, the UEperforms listen-before-talk (LBT). At step 203, the UE transmits a PUSCHin the scheduled subframe starting from one available starting positionof multiple candidate starting positions in the scheduled subframe ifthe LBT is successful. In particular, the PUSCH here is the firstly sentPUSCH in a burst, and the firstly sent PUSCH can end at the subframeending boundary of the scheduled subframe. According to this embodiment,after LBT succeeds, the UE selects a PUSCH start position from availablecandidate position(s). For example, the UE can send a PUSCH right afterthe LBT succeeds. It should be noted that any other signals (e.g.preamble, reservation signal, etc.) can also be sent before PUSCH ifnecessary. If there is no available candidate position after LBT or LBTis not successful in the scheduled subframe, the UE will not send PUSCHin this scheduled subframe.

An embodiment of the present disclosure also provides a UE for LAA toperform the above communication method. FIG. 3 schematically illustratesa block diagram of the UE 300 according to an embodiment of the presentdisclosure. UE 300 can comprise a receiver 301 operative to receive a ULgrant which schedules a subframe for UL transmission, a first circuit302 operative to perform LBT, and a transmitter 303 operative totransmit a first PUSCH in the scheduled subframe starting from oneavailable starting position of multiple candidate starting positions inthe scheduled subframe if the LBT is successful.

The UE 300 according to the present disclosure may optionally include aCPU (Central Processing Unit) 310 for executing related programs toprocess various data and control operations of respective units in theUE 300, a ROM (Read Only Memory) 313 for storing various programsrequired for performing various process and control by the CPU 310, aRAM (Random Access Memory) 315 for storing intermediate data temporarilyproduced in the procedure of process and control by the CPU 310, and/ora storage unit 317 for storing various programs, data and so on. Theabove receiver 301, first circuit 302, transmitter 303, CPU 310, ROM313, RAM 315 and/or storage unit 317 etc. may be interconnected via dataand/or command bus 320 and transfer signals between one another.

Respective components as described above do not limit the scope of thepresent disclosure. According to one implementation of the disclosure,the functions of the above receiver 301, first circuit 302 andtransmitter 303 may be implemented by hardware, and the above CPU 310,ROM 313, RAM 315 and/or storage unit 317 may not be necessary.Alternatively, the functions of the above receiver 301, first circuit302 and transmitter 303 may also be implemented by functional softwarein combination with the above CPU 310, ROM 313, RAM 315 and/or storageunit 317 etc.

As described in the above, in one scheduled subframe according to ULgrant sent by eNB, PUSCH can start in multiple predefined positions.After LBT succeeds at UE in the scheduled subframe, UE starts PUSCHtransmission at one of available predefined position(s). Therefore, thepossibility that PUSCH could be sent at the scheduled subframe after LBTis increased.

In an embodiment, there can be two candidate starting positions in thescheduled subframe, which are at the starting points of two slots of thescheduled subframe respectively. Accordingly, there are two candidatePUSCHs corresponding to the two candidate starting positions, wherein afirst candidate PUSCH (partial PUSCH) of the two candidate PUSCHs hasone slot length, and a second candidate PUSCH (normal PUSCH) of the twocandidate PUSCHs has two slot length.

FIG. 4 schematically illustrates an embodiment in which there are twocandidate starting positions for PUSCH in a subframe. As shown in FIG.4, one UL grant from eNB can schedule one PUSCH with 2 possible lengths(i.e. 1 slot or 2 slots) in the scheduled subframe, and the PUSCH canalways end at the subframe ending boundary of the scheduled subframe.After LBT succeeds, UE selects a PUSCH starting position from availablecandidate position(s). It should be noted that any other signals (e.g.preamble, reservation signal, and etc.) could also be sent before PUSCHif necessary. If there is no available candidate position after LBT orLBT is not successful in the scheduled subframe, UE would not send PUSCHin this scheduled subframe.

Since the PUSCH length is not predictable when UL grant is sent, itwould be necessary to prepare PUSCHs with two possible lengths (one slotor two slots). According to current UL grant (LTE Release 13), RBallocation, MCS, and number of transport block are indicated to UE.Depending on the assumed PUSCH length, the number of RE for PUSCHtransmission can be derived separately.

Regarding the transport block size, there can be two possibleapproaches. A first option is that two transport blocks (the normalPUSCH assumes N RB allocation and the partial PUSCH assumes └N/2┘ RBallocation, where N is the allocated RB number indicated in the ULgrant) are prepared for respective PUSCH lengths. In other words, in anembodiment, the UE can comprise a second circuit operative to preparetwo transport blocks respectively for the two candidate PUSCHs, whereinthe second candidate PUSCH (normal PUSCH) assumes └N/2┘ RB allocation,and the first candidate PUSCH (partial PUSCH) assumes └N/2┘ RBallocation, where N is the allocated RB number indicated in the ULgrant. Alternatively, a second option is that one transport block isprepared while reinterpreting the MCS in the UL grant for the partialPUSCH, for example, increasing the modulation order and/or code rate. Inother words, in an embodiment, the UE can comprise a second circuitoperative to prepare one transport block for the two candidate PUSCHs,wherein the modulation and coding scheme (MCS) indicated in the UL grantis reinterpreted for the first candidate PUSCH.

Concerning RE mapping, it is feasible to reuse current RE mapping(including time first PUSCH data mapping, PUSCH RS, CQI/PMI, ACK/NACK,RI as shown in FIG. 5) at each slot and TBS determination for a partialPUSCH with one slot length.

Current intra-subframe frequency hopping for PUSCH supports two slots indifferent frequency band. FIG. 6 schematically illustrates formation ofone slot length PUSCH by using the intra-subframe frequency hoppingaccording to an embodiment of the present disclosure. As shown in leftside of FIG. 6, the first slot (slot 0) of all allocated RBs is mappedon one subband while the second slot (slot 1) of all allocated RBs ismapped on another subband (in the same bandwidth as the previous one)which is several RBs away from the former subband. Then, as shown inright side of FIG. 6, by combining the allocated RBs in slot 0 with theallocated RBs in slot 1 into one slot (slot 1), the one slot lengthPUSCH can be obtained. That is, in time domain, those allocated RBs areput into one slot, and in frequency domain, they can be arranged in theoriginal order and continuously. In other words, in an embodiment, theUE can comprise a third circuit operative to form the first candidatePUSCH by combining allocated RBs in slot 0 and allocated RBs in slot 1of a two-slot length PUSCH with intra-subframe frequency hopping intoone slot.

Alternately, one shortened PUSCH with N−RB×1-slot can use the mappingfor a PUSCH with └N/2┘-RB×2-slot, where N is the allocated RB numberindicated in the UL grant. FIG. 7 schematically illustrates formation ofone slot length PUSCH by using mapping for a two-slot PUSCH according toan embodiment of the present disclosure. As shown in FIG. 7 assuming Nis an even number, in a first step, RE mapping for a 2-slot PUSCH withN/2 RBs is performed, and in a second step, each RB with 2 slots ismapped to 2 adjacent RBs with 1 slot. When N is an even number, allallocated RBs could be occupied by PUSCH with one slot length. If N isan odd number, one of allocated RBs might be dropped by PUSCH with oneslot length. According to this embodiment, the UE can comprise a thirdcircuit operative to form the first candidate PUSCH with N−RB×1-slot byusing the mapping for a two-slot length PUSCH with └N/2┘-RB×2-slot,wherein each RB with 2 slots is mapped to 2 adjacent RBs with 1 slot.

As described in the above, it is possible to minimize the specificationimpact as well as UE transceiver modification/complexity by usingslot-level candidate starting position (i.e. 2 starting candidates)since it is possible to reuse the RE mapping, TBS determination, andintra-subframe hopping. It is noted that the second circuit and thethird circuit may be implemented by hardware or by functional software,similar to the first circuit 302.

In another embodiment, the candidate starting positions can be in thesymbol level. One UL grant from eNB could schedule one PUSCH withmaximally 14 possible lengths (i.e. 1 to 14 SC-FDMA (Single-carrierFrequency-Division Multiple Access) symbols) in the scheduled subframe,e.g. 4 starting positions at symbol 0/4/7/11, in case of normal cyclicprefix. SRS (Sounding reference signal) symbol (the last SC-FDMA symbolin the uplink subframe) would be precluded in SRS subframe. After LBTsucceeds, UE selects one available PUSCH starting position. For thisembodiment, PUSCH should be prepared for multiple possible lengths, andnew TBS determination (e.g. scale factor) based on PUSCH length isneeded except for 13 symbol and 14 symbol lengths. The current transportblock size table defined in 3GPP TS 36.213 (3rd Generation PartnershipProject; Technical Specification Group Radio Access Network; EvolvedUniversal Terrestrial Radio Access (E-UTRA); Physical layer procedures)assumes normal PUSCH with 14 or 12 symbols depending on CP (CyclicPrefix) length, so PUSCH with less SC-FDMA symbols would have a scalefactor applied to the current TBS proportionally to the number of PUSCHdata REs. For example, the scale factor can be calculated by the numberof the PUSCH SC-FDMA symbols divided by 14. In addition, new RE mappingstarting from the first SC-FDMA symbol of PUSCH except for the 14 symbollength is needed. One approach is to reuse current UL subframe structurealigned with UL subframe structure (i.e. symbols 3/10 if normal CP andsymbols 2/8 if extended CP) in licensed carrier as shown in FIG. 8, inwhich PUSCH RS is always at predefined symbols. In this approach, thePUSCH SC-FDMA symbols in current UL subframe structure is truncated fromthe beginning. LB (long block) equals to SC-FDMA symbol. Anotherapproach is to shift the UL subframe structure i.e. all SC-FDMA symbolsshift from left to right in FIG. 8. In this approach, the UL subframestructure is truncated from the ending. For 13 SC-FDMA length of PUSCHstarting from the 2nd SC-FDMA symbol, DMRS shifting one SC-FDM symbolrightward from current subframe with SRS (in the last SC-FDMA symbol ofcurrent uplink subframe) is required.

In another embodiment, the transmitter of the UE can be furtheroperative to transmit a second PUSCH ending at the end of a burst. It isnoted that the “first” and “second” in “first PUSCH” and “second PUSCH”in the present disclosure do not limit the sequence of the PUSCHs, butonly to differentiate one PUSCH from another. Based on regionalregulations, the maximum length of a burst may be restricted, e.g. to 4ms in Japan and 10 ms in Europe. When one UL burst (consisting of atleast one UE's uplink transmission signal) has a partial subframe in thebeginning, a partial subframe in the end would be beneficial to reachthe maximum allowed occupation which is usually at 1 ms granularity. Howto schedule the partial subframe in the end of burst can have multipleapproaches. For example, one approach is to independently schedule thepartial subframe in the end of the burst by a separate UL grant as othersubframes, and another approach is to implicitly schedule the partialsubframe in the end of the burst by the UL grant for the partialsubframe in the beginning of the burst for the same UE, as shown in FIG.9. FIG. 9 schematically shows a burst with a partial subframe at the endof the burst to occupy the whole burst. As shown in FIG. 9, the partialsubframe at the end of the burst is not explicitly scheduled by aseparate UL grant, but implicitly scheduled by the UL grant for thepartial subframe in the beginning of the burst. In other words, if thefirst scheduled subframe of the burst is a partial subframe, the partialsubframe at the end of the burst is implicitly scheduled.

In another embodiment, the uplink partial subframe can be jointlyscheduled and/or jointly encoded with its adjacent normal subframe if UEis scheduled to more than one subframes successively. If the uplinkpartial subframe is in the beginning of the burst, its adjacent normalsubframe is the next subframe. If the uplink partial subframe is in theend of the burst, its adjacent normal subframe is the previous normalsubframe. For example, if the above-mentioned first PUSCH does not startfrom the subframe beginning boundary of the scheduled subframe, thescheduled subframe can be jointly encoded with its next subframe. If theabove-mentioned second PUSCH does not end at the subframe endingboundary of the last subframe of the burst, the last subframe can bejointly encoded with its previous subframe.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware. Each functional block used in thedescription of each embodiment described above can be realized by an LSIas an integrated circuit, and each process described in the eachembodiment may be controlled by LSI. They may be individually formed aschips, or one chip may be formed so as to include a part or all of thefunctional blocks. They may include a data input and output coupledthereto. The LSI here may be referred to as an IC, a system LSI, a superLSI, or an ultra LSI depending on a difference in the degree ofintegration. However, the technique of implementing an integratedcircuit is not limited to the LSI and may be realized by using adedicated circuit or a general-purpose processor. In addition, a FPGA(Field Programmable Gate Array) that can be programmed after themanufacture of the LSI or a reconfigurable processor in which theconnections and the settings of circuits cells disposed inside the LSIcan be reconfigured may be used.

It is noted that the present disclosure intends to be variously changedor modified by those skilled in the art based on the descriptionpresented in the specification and known technologies without departingfrom the content and the scope of the present disclosure, and suchchanges and applications fall within the scope that claimed to beprotected. Furthermore, in a range not departing from the content of thedisclosure, the constituent elements of the above-described embodimentsmay be arbitrarily combined.

Embodiments of the present disclosure can at least provide the followingsubject matters.

1. A user equipment for licensed-assisted access (LAA) comprising:

a receiver operative to receive an uplink (UL) grant which schedules asubframe for UL transmission;

a first circuit operative to perform listen-before-talk (LBT);

a transmitter operative to transmit a first physical uplink sharedchannel (PUSCH) in the scheduled subframe starting from one availablestarting position of multiple candidate starting positions in thescheduled subframe if the LBT is successful.

2. The user equipment according to 1, wherein

the first PUSCH ends at the subframe ending boundary of the scheduledsubframe.

3. The user equipment according to 2, wherein

there are two candidate starting positions in the scheduled subframe,which are at the starting points of two slots of the scheduled subframerespectively, and there are two candidate PUSCHs corresponding to thetwo candidate starting positions, wherein a first candidate PUSCH of thetwo candidate PUSCHs has one slot length, and a second candidate PUSCHof the two candidate PUSCHs has two slot length.

4. The user equipment according to 3, further comprising:

a second circuit operative to prepare two transport blocks respectivelyfor the two candidate PUSCHs,

wherein the second candidate PUSCH assumes N resource block (RB)allocation, and the first candidate PUSCH assumes └N/2┘ RB allocation,where N is the allocated RB number indicated in the UL grant.

5. The user equipment according to 3, further comprising:

a second circuit operative to prepare one transport block for the twocandidate PUSCHs,

wherein the modulation and coding scheme (MCS) indicated in the UL grantis reinterpreted for the first candidate PUSCH.

6. The user equipment according to 3, further comprising:

a third circuit operative to form the first candidate PUSCH by combiningallocated RBs in slot 0 and allocated RBs in slot 1 of a two-slot lengthPUSCH with intra-subframe frequency hopping into one slot.

7. The user equipment according to 3, further comprising:

a third circuit operative to form the first candidate PUSCH withN−RB×1-slot by using the mapping for a two-slot length PUSCH with└N/2┘-RB×2-slot, wherein each RB with 2 slots is mapped to 2 adjacentRBs with 1 slot.

8. The user equipment according to 1, wherein

the candidate starting positions are in the symbol level.

9. The user equipment according to 1, wherein

if the first PUSCH does not start from the subframe beginning boundaryof the scheduled subframe, the scheduled subframe is jointly encodedwith its next subframe.

10. The user equipment according to 1, wherein

the transmitter is further operative to transmit a second PUSCH endingat the end of a burst.

11. The user equipment according to 10, wherein

if the second PUSCH does not end at the subframe ending boundary of thelast subframe of the burst, the last subframe is jointly encoded withits previous subframe.

12. A wireless communication method for licensed-assisted access (LAA)performed by a user equipment, comprising:

receiving a uplink (UL) grant which schedules a subframe for ULtransmission;

performing listen-before-talk (LBT);

transmitting a first physical uplink shared channel (PUSCH) in thescheduled subframe starting from one available starting position ofmultiple candidate starting positions in the scheduled subframe if theLBT is successful.

13. The wireless communication method according to 12, wherein

the first PUSCH ends at the subframe ending boundary of the scheduledsubframe.

14. The wireless communication method according to 13, wherein

there are two candidate starting positions in the scheduled subframe,which are at the starting points of two slots of the scheduled subframerespectively, and there are two candidate PUSCHs corresponding to thetwo candidate starting positions, wherein a first candidate PUSCH of thetwo candidate PUSCHs has one slot length, and a second candidate PUSCHof the two candidate PUSCHs has two slot length.

15. The wireless communication method according to 14, furthercomprising:

preparing two transport blocks respectively for the two candidatePUSCHs,

wherein the second candidate PUSCH assumes N resource block (RB)allocation, and the first candidate PUSCH assumes └N/2┘ RB allocation,where N is the allocated RB number indicated in the UL grant.

16. The wireless communication method according to 14, furthercomprising:

preparing one transport block for the two candidate PUSCHs,

wherein the modulation and coding scheme (MCS) indicated in the UL grantis reinterpreted for the first candidate PUSCH.

17. The wireless communication method according to 14, furthercomprising:

forming the first candidate PUSCH by combining allocated RBs in slot 0and allocated RBs in slot 1 of a two-slot length PUSCH withintra-subframe frequency hopping into one slot.

18. The wireless communication method according to 14, furthercomprising:

forming the first candidate PUSCH with N−RB×1-slot by using the mappingfor a two-slot length PUSCH with └N/2┘-RB×2-slot, wherein each RB with 2slots is mapped to 2 adjacent RBs with 1 slot.

19. The wireless communication method according to 12, wherein

the candidate starting positions are in the symbol level.

20. The wireless communication method according to 12, wherein

if the first PUSCH does not start from the subframe beginning boundaryof the scheduled subframe, the scheduled subframe is jointly encodedwith its next subframe.

21. The wireless communication method according to 12, furthercomprising:

transmitting a second PUSCH ending at the end of a burst.

22. The wireless communication method according to 21, wherein

if the second PUSCH does not end at the subframe ending boundary of thelast subframe of the burst, the last subframe is jointly encoded withits previous subframe.

In addition, embodiments of the present disclosure can also provide anintegrated circuit which comprises module(s) for performing the step(s)in the above respective communication methods. Further, embodiments ofthe present can also provide a computer readable storage medium havingstored thereon a computer program containing a program code which, whenexecuted on a computing device, performs the step(s) of the aboverespective communication methods.

1. A base station comprising: a transmitter, which, in operation,transmits an uplink grant indicating a time resource used for an uplinkshared channel (PUSCH), the time resource comprising of a plurality ofsymbols; and a receiver, which, in operation, receives the PUSCHtransmitted from one position selected from multiple positions in thetime resource, wherein the multiple positions include a first symbol andan eighth symbol in the time resource, and a same transport block sizeis used in case of the PUSCH having a length of 14 symbols transmittedfrom the first symbol and in case of the PUSCH having a length of 7symbols transmitted from the eighth symbol.
 2. The base stationaccording to claim 1, wherein the PUSCH ends at least on a boundary ofthe time resource.
 3. The base station according to claim 1, wherein thefirst symbol is in a first half of the time resource and the eighthsymbol is in a second half of the time resource.
 4. The base stationaccording to claim 1, wherein the multiple positions are defined at asymbol level.
 5. The base station according to claim 1, wherein the timeresource is indicated by the base station before a result of a listenbefore talk (LBT) is determined.
 6. The base station according to claim1, wherein channel access based on a listen before talk (LBT) fails whena channel is busy.
 7. The base station according to claim 1, wherein theone position of the multiple positions is determined based on a resultof channel access of a listen before talk (LBT) performed by a userequipment.
 8. The base station according to claim 1, wherein the timeresource is a subframe.
 9. The base station according to claim 1,wherein the PUSCH is received using Licensed-Assisted Access (LAA). 10.A communication method comprising: transmitting an uplink grantindicating a time resource used for an uplink shared channel (PUSCH),the time resource comprising of a plurality of symbols; and receivingthe PUSCH transmitted from one position selected from multiple positionsin the time resource, wherein the multiple positions include a firstsymbol and an eighth symbol in the time resource, and a same transportblock size is used in case of the PUSCH having a length of 14 symbolstransmitted from the first symbol and in case of the PUSCH having alength of 7 symbols transmitted from the eighth symbol.
 11. Thecommunication method according to claim 10, wherein the PUSCH ends atleast on a boundary of the time resource.
 12. The communication methodaccording to claim 10, wherein the first symbol is in a first half ofthe time resource and the eighth symbol is in a second half of the timeresource.
 13. The communication method according to claim 10, whereinthe multiple positions are defined at a symbol level.
 14. Thecommunication method according to claim 10, wherein the time resource isindicated before a result of a listen before talk (LBT) is determined.15. The communication method according to claim 10, wherein channelaccess based on a listen before talk (LBT) fails when a channel is busy.16. The communication method according to claim 10, wherein the oneposition of the multiple positions is determined based on a result ofchannel access of a listen before talk (LBT) performed by a userequipment.
 17. The communication method according to claim 10, whereinthe time resource is a subframe.
 18. The communication method accordingto claim 10, wherein the PUSCH is received using Licensed-AssistedAccess (LAA).
 19. A communication apparatus comprising: a receiver,which, in operation, receives an uplink grant indicating a time resourceused for an uplink shared channel (PUSCH), the time resource comprisingof a plurality of symbols; and a transmitter, which, in operation,transmits the PUSCH from one position selected from multiple positionsin the time resource, wherein the multiple positions include a firstsymbol and an eighth symbol in the time resource, and a same transportblock size is used in case of the PUSCH having a length of 14 symbolstransmitted from the first symbol and in case of the PUSCH having alength of 7 symbols transmitted from the eighth symbol.
 20. Acommunication method comprising: receiving an uplink grant indicating atime resource used for an uplink shared channel (PUSCH), the timeresource comprising of a plurality of symbols; and transmitting thePUSCH from one position selected from multiple positions in the timeresource, wherein the multiple positions include a first symbol and aneighth symbol in the time resource, and a same transport block size isused in case of the PUSCH having a length of 14 symbols transmitted fromthe first symbol and in case of the PUSCH having a length of 7 symbolstransmitted from the eighth symbol.